Since news reports in early August revealed that the United States intercepted messages between Ayman al-Zawahri, who succeeded Osama bin Laden as the head of Al Qaeda, and Nasser al-Wuhayshi, the head of the Yemen-based Al Qaeda in the Arabian Peninsula, discussing an imminent terrorist attack, analysts have detected a sharp drop in the terrorists’ use of a major communications channel that the authorities were monitoring. Since August, senior American officials have been scrambling to find new ways to surveil the electronic messages and conversations of Al Qaeda’s leaders and operatives.

“The switches weren’t turned off, but there has been a real decrease in quality” of communications, said one United States official, who like others quoted spoke on the condition of anonymity to discuss intelligence programs.

Given what we know of the breadth and depth of NSA’s eavesdropping, you have to wonder if this new leak isn’t designed to make al Qaeda feel comfortable using whatever is their new high-level comms link — which NSA is also already listening to.